Smoke elbow for electric furnace

ABSTRACT

A tiltable electric furnace comprising an open-top chamber and a roof adapted to be lifted off the top of the chamber and movable between an operating position in which it is at least partially clear of the chamber for charging said chamber from the top. The roof has a smoke outlet for discharge of gases from within said chamber when the furnace is in operation with the roof in its operating position. A smoke elbow is provided for conducting gases from the smoke outlet in the roof to a duct, the elbow being mounted independently of the roof for movement relative to the chamber between an operating position wherein its inlet end is in communication with said smoke outlet for conducting gases from the outlet to the duct, and a retracted position wherein its inlet end is clear of the roof for movement of the roof to its said retracted position, the duct being movable between an operating position wherein its inlet end is engaged with the outlet end of the elbow when the elbos is elbow its operating position, and a retracted position wherein its outlet end is clear of the elbow for movement of the elbow to its said retracted position.

United States Patent [191 Bowermaster et al.

[ Nov. 13, 1973 [5 SMOKE ELBOW FOR ELECTRIC FURNACE [751 Inventors: Riley J. Bowermaster, Hartford, 111.;

Robert H. Becker, F lorissant, Mo.

[73] Assignee: Laclede Steel Company, St. Louis,

[22] Filed: Feb. 5, 1973 [21] App]. No.: 329,437

[52] U.S. Cl. 13/10, 266/16, 432/200 [58] Field of Search 13/1, 10, 33; 266/15, 16; 432/200, 201

[56] References Cited UNITED STATES PATENTS 3,379,426 4/1968 Reuter et al..... 266/15 X 3,428,301 2/1969 Chermely 13/10 X 3,533,611 10/1970 Boyer etal. 266/15 Primary ExaminerRoy N. Envall, .lr. Attorneylrving Powers et al.

[57] ABSTRACT A tiltable electric furnace comprising an open-top chamber and a roof adapted to be lifted off the top of the chamber and movable between an operating position in which it is at least partially clear of the chamher for charging said chamber from the top. The roof has a smoke outlet for discharge of gases from within said 'chamber when the furnace is in operation with the roof in its operating position. A smoke elbow is provided for conducting gases from the smoke outlet in the roof to a duct, the'elbow being mounted'inde- 'pendently of the roof for movement relative to the chamber between an operating position wherein its inlet end is in communication with said smoke outlet for conducting gases from the outlet to the duct, and a retracted position wherein its inlet end is clear of the roof for movement of the roof to its said retracted position, the duct being movable between an operating position wherein its inlet end is engaged with the outlet end of the elbow when the elbos is elbow its operating position, and a retracted position wherein its outlet end is clear of the elbow for movement of th elbow to its said retracted position.

13 Claims, 7 Drawing Figures PATENTEBNUY 13 191a 3; 772.448

SHEET 2 BF 4 PMENTEDnov 13 1975 SHEET 3 OF 4 FIG.4

SHEET u or 4 FIG.5

elbow to its retracted position.

SMOKE ELBOW FORELECTRIC- FURNACE BACKGROUND oF- THE- INVENTION Thisinvention relates to electric'furnaces, more particularly electric are-furnaces such as are used in steel making, and is especially concerned'with a so-called smoke elbow for such a furnace.

The invention is'especially-directed to an'electric arc furnace of the type'havingaroof which is movable awayfrom' the furnace chamber'for charging the chamber fror'nj theto'p; the roofhaving openingstherein for i the electrodes-ofthe furnace, and a smoke outlet'for dischargeof gasesfromthe chamber; the outlet being connected'by a'nelbow' to a ductfor conducting the gasestoair pollution control equipment. Reference maybe made to such U.S. Pats. as-No's; 1,224,788, 3,173,980, 3,358,978, 3,453,369 and"3,50l ,579 showing electric furnaces in the same general field as thisin vention.

SUMMARY OF THE INVENTION Am'ong'the several object'sof this invention may be "noted 'the provision of an electric furnace of the: type having a roof which-is'movable from'overthe furnace andthe provision of a' furnace which is tiltable for tap ping and slaggingwith a smoke elbow that may remain in an operative'position as the furnace is tilted.

Ingcner'al, ari-ele'c'tricfurn'ace of thisainvention comprisesan open-top chamber" and a roof movable between an operating position covering the chamber and a charging position in which it is at least'partially clear of the chamber for charging the chamber from the top. The roof has a smoke outlet for'discharge of gases from within the chamber when the furnace'is in operation with the roof in its operating position. A duct is provided for carrying away the gases, this duct havingan inlet end;- A smoke elbow is provided for conducting gases from the smoke outlet in the roof to the duct. The,

smoke elbow is mounted independently of the roof for movement relative to the chamber between an operating position wherein the inlet end of the elbow is in communication with the smoke outlet in the roof for conducting gases from the outletto the duct, and a retracted position wherein the inlet end of the smoke elbow is clear of the roof for movement of the roof to its retracted position. The duct is movable between an operating position wherein its inlet end is engaged'with the outlet end of the elbow when the elbow is in its operating position, and a' retracted position wherein its outlet end is clear of the elbow for movement of the Other objects and features will be in part apparent and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS tilted to a slagging position (the. tapping and slagging FIG .3 is an enlarged view of a portion of thefurnace,

shown in FIG. 2 .illustrating the operating position of the smoke elbow and a movable duct in-solid lines, and illustrating the retracted position .of thesmoke elbow and the duct in phantom;

FIG. 4-is a vertical section taken on line,44 of FIG.

FIG. 5 is a planof the furnace withits roof swung to its charging position;

FIG. 6- is a left-side elevation of the furnace shown in FIG. .1; with .its tilted tapping and .slagging positions illustrated in phantom; and I I FIG. 7-isapartial sideelevation of .a modification. of

the furnace of thisinvention -.with the outletendof the, smokeelbow andztheinletend .of the-.movableduct at, rightangles-to the center lines of thes'moke ,elbowand' duct, respectively.

Corresponding reference charactersv indicate corresponding parts throughout the; several views-of the drawings.

DESCRIPTION'OF THE PREFERRED v EMBODIMENTS Referring to the drawings, an electricarc furnaceof this invention, indicated in its entirety at l is shown to comprise an open-topped'furnace body or chamber 3 on a support or platform 5;.and a. removable roof; 7; The chamber-3 is-constituted by a steel shelllined'with suitable refractory materials tocontain the molten. metal-(and slag) therein. A pouring-spout=9 isprovided; at one side of the" furnace for pouring molten: metal from the furnace when it is'tilted to a tapping position, and a slagspout 11 is provided on the other-side of the furnace for pouring slag from the furnace when it it.

positionswill be more fully explained"v hereinafter).

Roof.7 is swingable laterally relative tothechamber on a roof lift and swing assembly generally indicated: at 13 about a vertical axis offset from the chamber 3, at one side thereof between an operating position (shown in FIGS. 1-3 and. 6) in which the roof covers and closes thetop of the chamber 3, and a charging position (FIG- 5 -in which. the roof is at least partially clear of the chamber for charging the chamber from the top thereof. As shown in FIG. 2, the roof lift and swing assembly includes a roof lift cylinder 15 and a ram 17 movable by the cylinder to engage a roof support structure generally indicated at 19 including a swing yoke 21 from which a pair of spaced suspension beams, each indicated at 23, is cantilevered for suspending the roof. A post 25 is rigidly mounted on platform 5 below each of the suspension beams 23 adjacent the inner end of the beam. Each of these posts has a pin 27 at its upper end for being received in a corresponding socket (not shown) in swing yoke 21 when the roof is in its operat ing position so as to locate and hold the roof in this positionrelative to the chamber 3. Yoke 21' has a pivot lug 29 having a bore 31 therein directly above ram 17 for receiving theram. Upon actuation of lift cylinder 15, ram 17 is thrust upwardly to be received in bore 31 in such manner that the roof support structure is lifted clear of pins 27 and the roof is lifted clear of the chamber 3. The roof may.then be swung about the vertical axis of ram 17 between-its charging and operating positions by suitable power operated means (not shown) as known in the art.

Platform 5 is mounted on a pair of rockers 33 which bear on a base structure such as indicated at 35, the chamber thereby being adapted for rocking or tilting from a generally upright position (shown in solid lines in FIG. 6) either to its tapping position in which its pouring spout 9 is down so that molten metal may be poured from the furnace, or to its slagging position in which slag spout 11 is down, the tapping and slagging positions being shown in phantom in FIG. 6. A hydraulic tilt cylinder 37 (see FIG. 6) is provided for rocking platform 5 and chamber 3 on rockers 33, between the stated upright position and tapping or slagging positions of the chamber 3. As shown in FIG. 6, the chamber is tiltable about 40 from the vertical to assume its tapping position and about from the vertical to assume its slagging position. The chamber may be tilted either to its tapping or its slagging position with roof 7 in its operating position.

Roof 7 has openings for three electrodes 39 adjacent its center. As known in the art,'the electrodes extend down through these openings in the operation of the furnace, and are vertically movable relative to the roof so that they may be fed into chamber 3 during operation of the furnace and raised clear of the chamber to permit swinging of the roof to its charging position. A' smoke outlet 41 is provided in the roof at the side thereof generally opposite swing yoke 21 for discharge of gases (smoke) from the chamber 3. In accordance with this invention, a smoke duct 43 is provided for carrying away the gases, and a smoke elbow 45 is provided for conducting gases from the smoke outlet in the roof to the duct. The duct has a beveled inlet end 47, inclined so as to open downward. The smoke elbow has one end 49 constituting its inlet end engageable with the smoke outlet 41, and its other end 51 constituting its outlet end engageable with the inlet end 47 of duct 43. For the latter purpose, outlet end 51 of the smoke elbow is beveled as appears in FIGS. 2 and 3, opening upward.

The smoke elbow 45 is mounted independently of the roof for pivotal movement relative to the chamber 3 (and the smokeoutlet 41) between an operating position (shown in solid lines in FIG. 3) wherein its inlet end 49 is in engagement with smoke outlet 41 at the outer end of the latter for communication therebetween for conducting gases from outlet 41 to the duct, and a retracted position (shown in phantom in FIG. 3) wherein its inlet end is clear of outlet 41 (and hence clear of the roof) to enable movement of the roof to its lifted and retracted position. The duct 43 is movable axially in any suitable manner between the operating position in which it appears in solid lines in FIG. 3 wherein its inlet end 47 engages the'outlet end 51 of the smoke elbow (the latter being in its operating position), and the outward retracted position in which it appears in phantom in FIG. 3 in which its inlet end 47 is clear of outlet end 5l;of the smoke elbow for movement of the elbow to its retracted position. With the outlet end of the smoke elbow and the forward end of the duct beveled as shown (e.g., at about 45),the duct need be axially retracted only a relatively small distance to permit pivoting of the smoke elbow between its operating and its retracted positions. In the event the use of beveled ends 51 and 47 on the smoke elbow 45 and duct 43, respectively, causes any problem, it may be desirable to modify them, as illustrated in FIG. 7, so that the outlet end of the smoke elbow and the inlet end of the duct are at right angles to the center line of the outer portion of the smoke elbow and the duct, respectively. This right angle outlet end of the smoke elbow is indicated at 51a and the right angle end of the duct is indicated at 47a to distinguish them from their corresponding beveled ends 51 and 47, respectively, shown in FIGS. l-6.

Smoke elbow has a pair of side plates 53 by means of which it is pivoted for swinging movement on a horizontal axis below and transverse to itself via a pivot pin 55 at the upper end of a pin support frame 56 extending up from platform 5 on the side of chamber 3 toward the duct 43. A hydraulic cylinder unit 57 is connected between the smoke elbow and platform 5 to swing the smoke elbow between its operating position (shown in solid lines in FIG. 3) and its retracted position (shown in phantom in FIG. 3). The smoke elbow is watercooled cooling water being supplied to cooling passages (not shown) in the duct by supply piping generally indicated at 59 and drained therefrom by drain piping generally indicated at 61. This supply and drain piping is carried by and is movable with the smoke elbow as the latter is swung between its operating and retracted position. As shown in FIG. 4, swivel connections 63 and 65 are included in supply piping 59 and in drain piping 61, respectively. These swivel connections are coaxial with shaft 55 so that the piping carried by the elbow is free to rotate relative to the stationary portions of the piping carried by platform 5 as the smoke elbow is swung between its operating and retracted positions.

With smoke elbow 45 mounted on frame 56 carried by the furnace platform 5, the smoke elbow is movable with the platform as the furnace tilts from its upright position either to its tapping or its slagging position. The furnace shown in FIGS. 1-6 is tiltable via rockers 33 to its tapping position with the smoke elbow in its operating position and with duct 43 in its retracted or second position (shown in phantom in FIG. 3), and may be tilted to its slagging position without moving either the smoke elbow or duct (i.e., with the smoke elbow remaining in its operation position and with the duct remaining in its first position). However, with the modified duct 43 shown in FIG. 7 having a right angle inlet end 47a and with the modified smoke elbow 45 having a right angle outlet end 51a, the duct must be retracted to permit tilting of the furnace to its tapping position (the smoke elbow may remain in its operating position). Furthermore, with the smoke elbow mounted on frame 56, the dead weight of the smoke elbow and its mounting structure is removed from the roof, thereby making it easier for the roof lift and swing assembly 13 to move the roof between its operating and its charging positions (and dead weight is also removed from chamber 3). And by constructing supply and drain piping 59 and 61 as above described, the piping need not be carried by the roof, thus allowing more room on the roof for routing the electrical cables supplying electrodes 39.

said chamber from the top, said roof having a smoke outlet for discharge of gases from within said chamber when the furnace is in operation with the roof in its operating position, a duct for carrying away the gases, said duct having an inlet end, a smoke elbow forconducting gases from the smoke outlet in the roof to the duct, said elbow having one end constituting its inlet end and its other end constituting its outlet end, means mounting said elbow independently of the roof for movement relative to said chamber between an operating position wherein its inlet end is in communication with said smoke outlet for conducting gases from the outlet to the duct, and a retracted position wherein its inlet end is clear of the roof for movement of the roof to its said retracted position, said duct being movable between an operating position wherein its inlet end is engaged with the outlet end of the elbow when the elbow is in its operating position, and a retracted position wherein its outlet end is clear of the elbow for movement of the elbow to its said retracted position.

2. An electric furnace as set forth in claim 1 wherein said elbow mounting means carries the elbow for swinging movement about a generally horizontal axis offset from and extending transversely of the elbow.

3. An electric furnace as set forth in claim 2 wherein the duct has its inlet end movable generally horizontally toward and away from the outlet end of the elbow. 4. An electric furnace as set forth in claim 3 wherein the inlet end of the duct is beveled to open downward and the outlet end of the elbow is beveled to open in upward direction when engaged by the inlet end of the duct.

5. An electric furnace as set forth in claim 1 wherein said chamber is mounted on a support, and said elbow mounting means comprises an elbow supporting means mounted on the support and means mounting the elbow for swinging movement on said elbow supporting means about a generally horizontal axis offset from and extending transversely of the elbow.

6. An electric furnace as set forth in claim 5 wherein the duct has its inlet end movable generally horizontally toward and away from the outlet end of the elbow, and wherein the inlet end of the duct is beveled to open downward and the outlet end of the elbow is beveled to open in upward direction when engaged by the inlet end of the duct.

7. An electric furnace as set forth in claim5 wherein said support comprises a platform mounted for tilting movement to tilt said chamber for tapping and slagging, said elbow being movable with said platform and chamber as they tilt and swingable on its said horizontal axis relative to said chamber and platform.

8. An electric furnace as set forth in claim 7 having means for swinging the roof laterally relative to the chamber about a swing axis on one side of the chamber between its said operating and retracted positions when said elbow is clear of the roof.

9. An electric furnace as set forth in claim 8 wherein the said roof is also movable upwardly away from and downwardly toward said chamber, and wherein the pivotal axis of the elbow is located for the elbow to be clear of the roof when the roof is raised.

10. An electric furnace as set forth in claim 9 wherein said elbow mounting means comprises a pivot support extending up from the platform on the side of the I chamber opposite the swing axis of the roof, the elbow being pivoted atthe upper end of said pivot support.

11. An electric furnace as set forth in claim 10 wherein the elbow is pivoted at the upper end of said pivot support in such manner that the inlet end of the elbow extends down toward the roof and its outlet end is aligned with the duct when the elbow is in its operating position.

12. An electric furnace as set forth in claim 1 1 having means for water-cooling the elbow including piping having swivel connections in line with the pivotal axis of the elbow.

13. An electric furnace as set forth in claim 1 1 having hydraulic cylinder means interposed between the platform and elbow for swinging the latter. 

1. An electric furnace comprising an open-top chamber, a roof movable between an operating position covering the chamber and a charging position in which it is at least partially clear of the chamber for charging said chamber from the top, said roof having a smoke outlet for discharge of gases from within said chamber when the furnace is in operation with the roof in its operating position, a duct for carrying away the gases, said duct having an inlet end, a smoke elbow for conducting gases from the smoke outlet in the roof to the duct, said elbow having one end constituting its inlet end and its other end constituting its outlet end, means mounting said elbow independently of the roof for movement relative to said chamber between an operating position wherein its iNlet end is in communication with said smoke outlet for conducting gases from the outlet to the duct, and a retracted position wherein its inlet end is clear of the roof for movement of the roof to its said retracted position, said duct being movable between an operating position wherein its inlet end is engaged with the outlet end of the elbow when the elbow is in its operating position, and a retracted position wherein its outlet end is clear of the elbow for movement of the elbow to its said retracted position.
 2. An electric furnace as set forth in claim 1 wherein said elbow mounting means carries the elbow for swinging movement about a generally horizontal axis offset from and extending transversely of the elbow.
 3. An electric furnace as set forth in claim 2 wherein the duct has its inlet end movable generally horizontally toward and away from the outlet end of the elbow.
 4. An electric furnace as set forth in claim 3 wherein the inlet end of the duct is beveled to open downward and the outlet end of the elbow is beveled to open in upward direction when engaged by the inlet end of the duct.
 5. An electric furnace as set forth in claim 1 wherein said chamber is mounted on a support, and said elbow mounting means comprises an elbow supporting means mounted on the support and means mounting the elbow for swinging movement on said elbow supporting means about a generally horizontal axis offset from and extending transversely of the elbow.
 6. An electric furnace as set forth in claim 5 wherein the duct has its inlet end movable generally horizontally toward and away from the outlet end of the elbow, and wherein the inlet end of the duct is beveled to open downward and the outlet end of the elbow is beveled to open in upward direction when engaged by the inlet end of the duct.
 7. An electric furnace as set forth in claim 5 wherein said support comprises a platform mounted for tilting movement to tilt said chamber for tapping and slagging, said elbow being movable with said platform and chamber as they tilt and swingable on its said horizontal axis relative to said chamber and platform.
 8. An electric furnace as set forth in claim 7 having means for swinging the roof laterally relative to the chamber about a swing axis on one side of the chamber between its said operating and retracted positions when said elbow is clear of the roof.
 9. An electric furnace as set forth in claim 8 wherein the said roof is also movable upwardly away from and downwardly toward said chamber, and wherein the pivotal axis of the elbow is located for the elbow to be clear of the roof when the roof is raised.
 10. An electric furnace as set forth in claim 9 wherein said elbow mounting means comprises a pivot support extending up from the platform on the side of the chamber opposite the swing axis of the roof, the elbow being pivoted at the upper end of said pivot support.
 11. An electric furnace as set forth in claim 10 wherein the elbow is pivoted at the upper end of said pivot support in such manner that the inlet end of the elbow extends down toward the roof and its outlet end is aligned with the duct when the elbow is in its operating position.
 12. An electric furnace as set forth in claim 11 having means for water-cooling the elbow including piping having swivel connections in line with the pivotal axis of the elbow.
 13. An electric furnace as set forth in claim 11 having hydraulic cylinder means interposed between the platform and elbow for swinging the latter. 